(184) 
5-. A variety of Experiments have been made, and 
reafoning ufed in England and France, to prove the 
Truth ot the cc^mmon Opinion; but they do not en- 
tirely fatisfie all the Gentlemen on the other fide of 
i 
the Queftion. The prefent ingenious ProfefTor of Ma- 
thematicks and Philofophy at Vtrecht tells us in the 
Pretace to his Epitome Elementorum Vhyfico-Mathemati- 
corum^ publifli’d this Year, Anno 1716, In corporum mo~ 
torum virthus fupputandis amplexus Jum fententiam Cl. 
Leibnitfii, Hugenii, Poleni, S. Gravefandii, & antiquce 
valedixi, quam haflenns foveram, & docueram : Neque 
me rstinuerunt argumenta donijfmorum virorum in Galliis 
© Britannia eandem defendentium> 
Et quandd experimenta a Poleno 'S Gravefandio 
defcripta examinantur G? injpiciuntur, tarn manifejlo <- 
v/ficunt vires corporum percutientium effe in ratione com- 
pofita ex qua^rata velocitatum, & f.mplici maj/arum, ut 
illis fuhjcr there teneamur, nifi apertijfimis contradicere flu- 
deamus. 
6. I beg leave to examine the truth of the new 
Opinion in the Cafe here propofed, viz. Vires corporum 
percutientium ; and I lhall endeavour to fliew from 
their own Principles, that it cannot be true in all the 
Cafes of Non Elaftic Bodies. 
7. ’Tis allow’d, that the common Rules of finding 
the Velocities of Non-Elafiic Bodies after the Stroke 
are true : For thus the ingenious Mr. S. Gravefand 
tells us in Paragraph 25*1, ot his Supplementum Pkyji- 
cum ; Ex hoc principio (^i. e. multipUcando majfam per velo- 
citatem) deduxere P'hilofophi ipfas illas regulas n. 234. /i^ 
237.7^ quas nos variis modis ex principiis noflris deduxi- 
mus ; mirum hie quid contigit , error err oris fuit dejlruc- 
tio, Gs? duplex^ error ad veritatem conduxit ; faljum de 
menfura virium fecuti funt principtum, ^ quod veritati 
etiam minime congruum eft, mllam vim intro premendo 
partes 
